It has previously been disclosed in the article, "Passenger Car Ventilation By Design," by Karl Wilfert, et al., published at the May 17, 1965 meeting of the Society of Automotive Engineers, to provide an automobile with a flow-through ventilation system, including an air inlet adjacent the windshield. This ventilation system depends upon dynamic pressure created by movement of the automobile. However, in this system, the air flow is from the front to the rear of the automobile, and is discharged through exit openings adjacent the rear window or trunk of the automobile. Thus, there is no disclosure in this article of a truck cab ventilation system in which air adjacent the ceiling of the truck cab is transmitted through a channel downward, to an exhaust vent positioned adjacent the floor of the cab, and discharged through an exit opening in the floor of the cab to the exterior of the truck cab in the manner of the present invention.
The exhaust vent employed in the ventilation system of the present invention employs movable louvers which are moved by air flow from a closed position to an open position, and which are normally held in a closed position by gravity, such louvers being preferably made of flexible elastomer material.
The truck cab exhaust ventilation system of the present invention has the advantage of automatically removing stale or hot air from the interior of the truck cab and exhausting such hot air to the exterior of the cab through an exhaust vent adjacent the floor of the cab. As a result, the driver in the truck cab can keep the cab windows closed to reduce wind noise and keep dust and other air contaminants from entering the truck cab. A positive air pressure is produced within the truck cab by the air inlet of a flow-through ventilation system in addition to such exhaust system. This positive air pressure causes air to flow through the exhaust ventilation system in an air flow channel extending from an upper portion adjacent the ceiling of the truck cab, down through a vertical portion to the exhaust vent positioned adjacent the floor of the truck cab, and discharged through an exit opening in the floor. As a result, hot air normally trapped adjacent the ceiling of the cab will be exhausted through such a vent to the exterior of the cab.